Electrical connecter plug



Feb. 5,1935. J. E. SMITH 1,989,949

I ELECTRICAL CONNECTER PLUG Original Filed Sept. 29, 1930 CURRENT imiimii S U IX IIIIIIIIIII Patented Feb. 5, 1935 I PATENT orties.

r 4,989,949 T CA CONNEcT R PLUG} John E. zsmith yBelleville.

M narch, Company, ,B llcville,,. i111 J a hornorar tion. o Mis our fll'iginal application 1 September 29, 1930, Serial N9. 4.84.,959 wDiwidedt-his application No! somber :2 .Serial I a cla m -711 L :relates .to an electrical connector plug and is shown as more particularly applied tothat type .of plug intendedto be -detachably con nected to electrical appliances.

' Mypresent application. is a divi'sion of mylce pending application Serial No. 484,950 for Elem tr-ical connector plugs, filed September-29,1930.

Itis .a fmther object of my invention to provide a resistor the form of a coiled guard tor I the current supply wires, said resistor being in circuit with electric appliance and an indicator lamp: being connected across said resistor.

Other and further objects ofmy invention be apparent from the following !spe ciflcation taken inwconjunction with the accompanying drawingwherein: l I I Figure 1 is a front elevation of my-improved connecter plug. a

I Figure 2 is a rear elevation of ithe same.

Figure Bisa side elevation of the plug. Figure 4 is 'a front elevation of the plug with" the top half thereof removed; and I ;;Figure 5 is a diagram showing the circuit non nections .to andin my improved connecter plug.

My invention contemplates an indicator lamp connected. in a shunt circuit through the appliance so that if the lamp should burn out, the appliance' can be used without the lamp ha ving tube-replaced; V

In order to'protect the lamp from damage by being in an exposed position, I arrange the "lamp within the body of the :connecter plug; However, itwis'notpractical to use a 1'10 volt lamp the connector plug, even if it were practical to get alamp. of .such .a voltage the confined area of the hodyiofzthe plug, diorthe reason that the heat of the lamp wouldbe so great itwouldafiect the a l o widen the plug is. composed and men.- J aps ca other ma e the connections; as en as. rendetinsthcrlus uncomi rtably nptio handle. r

a T e f rei- I propose to use an ordinary iflasn igh u r ui g, but 2 to -v 1ts and drawing ut 200. milliamperes or" current. Such a. low

watta e lamp will generate practically no heat and cer ain y none of a serious character within he space permitted on that-interior or, a

am. ena d tozusesuch alow voltage lamp :by cement n t e same abouts resistor so asf'to ake the drop thereaoross,-.the resistor being in sfinieswcirouit with the. circuit. through .said ap-u pliance. Howevenwit is important that the resistor ,shall :notv abe :confined within the body of theiplug iorit is=apparentthat:thelenergy consumed thereinswould be dissipated in heat and that heat'liberated within the body of the plug would be as undesirable as if a volt lampwere used. J

, Accordingly, I propose to arrange the resistor wire outside the plug. My arrangement substitutes the resistorfor the coiled spring guard usually found on connection. plugs where .the connector 'IGOJid. enters theplug.

Inasmuchas the indicator lamp may burn .out and therefore need replacement, I provide an openingfi n one half of my improved connector plug through which theconcealed lamp may be removed and .a Iresh lamp inserted and over the. opening a provide an apertured guard.

-Heferring .to: the drawing, my improved'plug is tormedoftwn pieces, an :upper half 11 and a lower half 12. vAll .of the electrical connections in the plug are locatedin the lower half oi the plug, the connecting .strips, etc., being embedded. in appropriate grooves :01 channels; Wherever it is" necessary, the upper half 11 has complementary grooves tor channels cooperating with those- :of the lower half to properly enclose the plugiand its connections. As this is the usual practice this. .art, it is only believed necessary to describe in detail the lower half of the plug, shown inFigA. I

At-thereducedend '13 .of the plug,*there are '10:- cated .twocohannels 14 and. 15 terminating in openings at the end .of the plug. 'In these channels. are embedded spring clips 16 and 1'7, respectively. These clips may be of any .of the usual'zand well known .constructions adapted to engagethe projecting lpins- 16a and 17a 'ordinarily constituting the terminals of .the heating element E of an electric appliance (see Figure 5).

Howeven'the clip 1"7 is provided with an .extension 18, the purpose of whichwill be more'tuHyhereinafter set forth. 1

' The channels 14 and 15 are of a considerable depth toaccommodatethe clips 16 and l'l gbut the flat'terminalportion-190i each clip rests in a groove that is only-deep enough to accommodate it. I

A pair of :metal strips 21 and 22 join respectively with-the terminals 19 of thespring clips 1-6 and 17, screws 23 serving to hold the strips and the terminals in electrical engagement with each other. The screws engage in screwthreaded bushings, not shown, which bushings are embedded in the insulatingmaterial of which the plug-is-eomposed. The connecting strips -21 and 22{rest in appropriate channels or grooves of a shape and size to accommodate *the strips which terminate respectively at terminal screws 24 and 36. It will be noted that the strips 21 and 22 extend longitudinally of the plug adjacent the opposite side edges thereof. Between the channels for these strips is located an enlarged cutout portion or pocket 26 adapted to house an indicator lamp 27.

The indicator lamp 2'? comprises a bulb 28, which is shown as rounded, housing a filament 29. Such lamps are ordinarily provided with a screw-threaded metallic shell 31 onthe base portion constituting one of the terminals of the filament 29. A terminal 32 on the end of the base constitutes the other terminal for the filament 29, the two terminals 31 and 32 being insulated from each other. I j

The base of the lamp 27 is received in a substantially semi-circular or U-shaped spring clip 33 (see Figure 4) which has a metallic strip 34 secured thereto. It will be noted that the strip 34 passes under the connecting strip 22 and ata third terminal screw 36 that is located at the center of the plug.

It will be noted that the connecting strips 21.

and 34 bend downwardly, while the connecting strip 22 bends upwardly in Figure 4 in order to properly space theterminal screws 24, 36 and 25 from each other.

I propose to use an ordinary two wire connecter cord, the wires of which are indicated at 41 and 44. The conductors 41 and 44 are connected respectively to the terminal screws 24 and 25, thus establishing electrical connection with the connecting strip 21 and the spring clip 16.

I have arranged a resistor 63 in the form of a coil and disposed at the same place where the connecter cord enters the. connecter plug, the coil resistor 63 thus taking the place of a coiled spring guard. The resistor 63, of course, is insulated as illustrated so as to prevent any possibility of it shocking or burning the user While energized.

The lowermost turn of the resistor 63 is of a diameter to fit into an annular groove 64 while the coil itself extends through a bore 42 of the plug. At the upper end of the coil, 1 provide an insulated ring 65 protecting the upper coil of the guard, as is the usual practice.

One end of the resistor 63 is connected to the terminal screw 36, the other end extending down through the coil alongside the connecter cord and terminating beneath the terminal screw 25.

The resistance wire 63 is chosen to have a predetermined ohmic resistance, the IR drop across which corresponds to the voltage required to properly energize the lamp 27. I have found that the flash light lamp requires but 2.2 volts to operate it. The wire 44 being connected with the terminal screw 25, supplies current to the strips 22 and 19 and to the projection 18.

Communicating with the pocket 26 is a cylindrical bore 51 which is made of a size and length suflicient to receive a coiled spring 52. One end of the spring 52 is closed by a plate 53 against which the terminal 32 of the lamp rests when the lamp is in place. Thus the electrical connection is made from the terminal 19 of the clip 17 through the arm 18, spring 52 and plate 53 to the terminal 32 of the lamp. This is the connection which is designated generally by the reference numeral 48 in the circuit diagram of Figure 5.

A projection 55, at the opposite end of the pocket 26, is formed of the material of which the plug is composed and extendsinto the pocket 26 so as to engage the end of the bulb 28. As the lamp 27 is inserted in place in the plug, it must be pressed home between the projection 55 and the plate 53 and this is suflicient to slightly compress the coiled spring 52. The lamp 27 is then held firmly from movement longitudinally of the plug by this arrangement and it is held from movement sidewise of the plug by the semi-circular spring clip 33.

The two halves of the plug 11 and 12 are held together by two or more screw bolts indicated at 57, these passing. through appropriate holes 58, extending through the halves of the plug and locatedin-the par'tsthat are thickest, that is to say, where there areno grooves or cutaway portions. When the two halves of the plug are assembled in this manner, the coiled resistor 63 is retained in position relative to the plug by the portion of the resistor mounted in the semi-cylindrical groove 64 of each half of the plug.

' In order that the lamp may be removed from the plug without removing thebolts '57, I make the opening 61a in the front of thezplug sufiiciently-large;andcircular to permit the passage of the lamp 27 therethrough. Over this opening I provide a grille or guard 64a which is riveted to the outside of the upper half 11- of the plug, as indicated at 65a. The riveting, is intended to hold the grille or guard 64a in frictional engagement with the surface of. the plug 11 so that it may be pushed aside, pivoting on the rivet to permit the lamp to pass through the opening 61a.

A stop 66 is provided on the plug along one edge of the guard 64c so as to limit its movement in one direction.

When it is desired to replace the lamp 27 in the plug, any instrumentality, such as a match, may be inserted in the rear aperture 62 to press the bulb 28 upwardly and out through the opening 61a after the grille 64a has been moved out of the way. Here, a person taking hold of the bulb 28 with his fingers can readily extractthe same from the plug. A fresh lamp is reinserted through" the opening 61 so that the base thereof engages in the clip 33, whereupon a simple pressure upon the lamp 27 with the finger will force the lamp home, the rounded surfaceof the bulb 28 serving as a cam on the abutment 55 to push the lamp 27 longitudinally in the clip 33-and to cause engagement of the terminal 32 on the lamp with the plate 53. After the lamp is inserted in place, the grille 64a is returned over'the opening 61.

Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims, any modified forms of structure or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention: I

1. In combination, an electrical connecter'plug adapted to connect an appliance which has an electrical element therein in circuit with a current supply outlet, said plug comprising a pair of con tact members having circuit connections thereto, a two-wire connecter cord extending between said outlet andplug and a coiled wire guard about the connecter cord where it enters the connecter plug, said guard being formed of insulation covered electrical resistor wire, the opposite ends of which are connected with one of said contact members and with one end of the electrical element of said appliance, an indicator lamp and means for mounting said indicator lamp on said plug in shunt circuit with said resistor Wire.

2. An electrical connecter, plug comprising a body portion, a signal device carried thereby, a pair of prong receiving sockets at one end of said body portion, a coiled wire guard at the other end thereof and a two wire connecter cord 5 extending through said coiled wire guard, said guard being formed of insulation covered electriconnected in series circuit between one of the connecter cord wires and one of said prong receiving sockets and means for connecting said signal device in parallel with said resistor wire.

JOHN E. SMITH. 

